Intermittent absorption refrigeration



June 27,1950 c. c. ccaorA 2,513,148

l IN'I'ERIIIIT'I'ENT ABSORPTIUNREFRIGERATIION v Filed Aug. 22, l1946 v 2Sheets-Sheet v2' INVENroR. Cuffia C. 600128 WMA? SIM Patented June 27,1950 INTEBMITTENT ABSORPTION REFRIGERATION Curtis C. Coons, NorthCanton, Ohio, assigner to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application August 22, 1946, Serial No. 692,267

1s claims. l

The present invention relates to the art of refrigeration and moreparticularly to a secondary cooling and control system for cooling andregulating the cooling of an element which is alternately subjected toheating and cooling cycles of operation.

Specifically the present invention proposes a cooling system for adevice alternately subject to periods of heating and cooling operationcharacterized by the provision of a means having no moving partsautomatically operable to interrupt the circulation of the coolingmedium when the aforesaid device is heated and to restore circulation ofthe cooling medium quickly at the termination of a heating cycle.

In a specic sense the present invention is particularly applicable to asecondary cooling system for the generator-absorbers of a dual unitintermittent refrigerating device. In accordance with the invention thecooling system is provided with a vapor lock arrangement which is heatedwhen heat is applied to the generator-absorber so as to interrupt thecirculation of the cooling medium. Cooling medium flow is theninterrupted simply by means of an entrapped body of vapor. 'I'he vaporlock is eliminated by the application of heat to the associatedgenerator-absorber whereby an excess pressure is applied to certainportions of the first-mentioned cooling system which operates to destroythe vapor lock and restore the circulation of the cooling medium.

Other objects and advantages of the invention will become more apparentas the description proceeds when taken in connection with theaccompanying drawings in which:

Figure 1 is a diagrammatic representation of a dual intermittentabsorption refrigerating system embodying the present invention;

Figure 2 is a diagrammatic fragmentary view showing a modified form ofthe invention of Figure 1;

' Figure 3 is a fragmentary vertical sectional view of a refrigeratorcabinet showing the arrangement of certain parts of the presentinvention with respect to the cabinet; and

Figure 4 is a rear partial elevational view of the arrangement of Figure3.

Referring now to Figure l 'of the drawing, it will be seen that theapparatus comprises two identical intermittent absorption refrigeratingsystems. Since the two systems are identical, the apparatus on theleft-hand side of Figure 1 will be given reference characters, and thecorresponding parts in the right-hand system of Figure 1 will be givencorresponding reference characters distinguished by a prime.

` The left-hand system of Figure 1 comprises a generator-absorber Aconnected by a conduit II to a tubular air-cooled condenser C whichdischarges condensed vapor through conduit I2 into the reservoir I3 ofan evaporator E.

This apparatus is provided with a gas burner I5 which is arranged todischarge products of combustion into the central heating flue I6 of thegenerator-absorber A. When heat is applied from the burner l5,refrigerant vapor is evolved from the absorber contained in thegeneratorabsorber A, which vapor flows through conduit Il, is liqueed incondenser C, and discharges through conduit I2 into the reservoir I3 ofthe evaporator E.

At the termination of a generating period, the control mechanism, to bedescribed hereinafter, de-energizes the gas burner I5 and a coolingmechanism, also to be described hereinafter, cools thegenerator-absorber A. As a result of this action the pressure within theabsorbent containing portion of generator-absorber A drops to a lowvalue and causes evolution of vapor from the liquid contained inevaporator E and at a low refrigerating temperature. The vapor soproduced flows from reservoir I3, through conduit I2, condenser C, andconduit II into the generator-absorber A wherein it is reabsorbed andthe heat of absorption is rejected to an ultimate cooling medium by theaction of the aforesaid cooling system.

The generator-absorber A comprises, in addition to the heating flue I6,a sealed tubular jacket Il surrounding tube I6 for the reception of acooling medium. The cooling jacket I1 is in turn surrounded by anabsorbent containing construction indicated generally in the drawings atI8. The specific construction of the generator-absorber as such forms nopart of the present invention. The system will be charged with asuitable refrigerant such as ammonia and a dry or liquid absorbent forthe refrigerant such as strontium chlorideor water.

Fuel for the fuel burners I5 and I5' is conducted from gas supplyconduit 20 through conduits 2l and 2|', respectively, to the burners I5and I5', respectively. Conduit 2I is provided with a solenoid controlvalve 22 around which is connected a small by-pass conduit 23. The fuelpassing through valve 22 and by-pass conduit 23 is conducted by conduit24 to the burner structure. The burner per se forms no part of thepresent invention but is preferably of the type embodying an automaticpilot or minimum ignition llame arrangement and a flame failure safetycut-off.

A thermostat 26 is associated with the generator-absorber A and isarranged to operate a snap acting electrical switch mechanism 21. In theposition shown, the electrical switch mechanism is energizing thesolenoid valve 22 through the following circuit: line wires 28 and 29,conductor 30, conductor 3|, the left-hand contact of switch 21, andconductor 32.

As the generator-absorber A reaches the end `of its heating period, thetemperature thereof begins to rise due to the reduced evolution ofrefrigerant vapor therefrom. When this temperature reaches apredetermined point, the thermostat element 26 will expand and actuatethe switch 21 to its opposite position de-energizingv solenoid valve 22and energizing solenoid valve 22'.

In the positions of the thermostatic elements 26 and 26' shown, theburner I5 has just been energized for a short period of time. As aresult, the thermostat 26 is collapsed because the burner has not hadtime to heat the generatorabsorber A to any appreciable degree. On theother hand, the thermostatic element 26' is expanded because thetemperature of the external casing of the generator-absorber A' has notyet been lowered appreciably. However, as the generator-absorber Aapproaches the end of its heating cycle, the generator-absorber A' willhave been cooled to a comparatively low temperature and the thermostat26 will be collapsed, thus expansion of the thermostat 26 Will actuatethe snap switch 21 without interference from the thermostat 26'. Thisalternate heating of the two generator-absorbers proceeds automaticallyas long as the system is energized.

The absorber-generator A has associated with its cooling jacket I1 asecondary cooling system comprising a vapor discharge conduit 35 for thejacket I1 which conducts vapor into the aircooled condenser 36. Thecondensate formed in condenser 36 ows through a conduit 31 into areservoir 38. From reservoir 38 a conduit 39 conveys cooling liquid tothe inlet leg 40 of a vapor lock conduit comprising conduits 40, 4I, and42 arranged in the form of an inverted U with the bight conduit 4Ipassing over the upper or discharge end of the products of combustionflue I6 of the generator-absorber. The discharge leg' 42 of the vaporlock construction forms a U-shaped trap conduit with the conduit 43which opens into the upper end of cooling jacket I1. This system will becharged with a suitable coolant such as methyl chloride.

The reservoirs 38 and 38' have the upper portions thereof connected by aconduit 45 for a purpose to be hereinafter described.

During cooling operation of the generatorabsorbers, the conduit systemconnecting the reservoir to the generator-absorber cooling jacket issubstantially filled with liquid in the manner shown for thegenerator-absorber A. However, at switchover, when the burner I isactuated to full flame operation, the heat applied to conduit 4Ivaporizes some of the liquid therein contained almost as soon as theflame reaches full volume on the burner itself. The vapor formed inconduit 4I lls the conduit 4I and extends into the conduits 40 and 42 toestablish a condition of vapor lock which prevents any further flow ofliquid from Kreservoir 38 into the cooling jacket I1.

Since liquid ow into jacket I1 is no longer possible, the liquidcontained in the jacket is rapidly vaporized and passes through conduit35 to condenser 36 wherein it is condensed and is discharged in liquidform through conduit 31 into the reservoir 38. Thus a short time afterswitchover to heating cycle operation substantially all the liquid inthe system is contained in reservoir 38 except for the small amountpresent in conduits 39, 40, 42, and 43.

As the heating cycle continues, there will be some evaporation of liquidin conduits 4I! and 42 due to heat conducted along the length of thatconduit until a condition of balance is reached which is roughlyindicated by the liquid level as shown in the conduits 40 and 42. Such acondition is achieved when the conduits 40 and 42 are at thecondensation temperature of the cooling medium at the surface level ofliquid therein. It will be understood, however, that this showing ofliquid levels in conduits 40 and 42 represents a possible condition; theliquid levels may be higher than shown 0r slightly lower, depending uponvarying ambient conditions, rate of heat application, and designfactors.

The conditions indicated in Figure 1 of the drawing will obtain untilthe thermostat 26 is actuated to de-energize burner I5 and to providefor full flame operation of burner I5'. As soon as the burner I5 isextinguished, the conduit systems 40, 4I, and 42 will begin to be cooledby the surrounding air and by air flowing through the ue I6. However,air ilow through flue I6 discharges heated air against conduit 4I,though the temperature of such air is materially below the temperatureof the products of combustion which impinge upon that conduit during theheating cycle of operation.

If the foregoing condition is allowed to proceed undisturbed, aconsiderable period of time, possibly twenty minutes, may be required tocondense the vapor in conduits 4U, 4I, and 42 completely to destroy thevapor lock and to permit circulation of cooling fluid from the reservoir38 into the jacket I1.

The aforementioned delay is an undesirable feature and it is one of theprincipal objects ol the present invention to abolish or destroy thevapor lock within a very short period of time.

It will be noted from Figure 1 that the conduit 31 extends into thereservoir 38 for a considerable distance and that its lower end isappreciably below the surface level of stored liquid in reservoir 38.

Very shortly after the thermostat 28 operates to de-energize burner I5and energize burner I5', the vapor lock in conduits 40', 4I', and 42'will be created. In addition to this, there will be a rapid vaporizationof cooling liquid which substantially fills the jacket I1. The rapidvaporization of the large quantity of liquid contained in jacket I1'produces an immediate and substantial increase in pressure in the entirecooling system associated with absorber-generator A'. This increase inpressure is applied to the upper portion of the reservoir 38 through.the conduit 45. Due to the fact that the lower end of conduit 31 issubmerged in the liquid in reservoir 38, the increase in pressureapplied from the cooling system of the generator-absorber cannotdirectly be applied to condenser 36 but liquid is forced to rise withinconduitl 31 from reservoir 38. The rising column of liquid in conduit 31creates a slight increase in pressure in the condenser 36. However. thatcondenser and its contents have long since reached a condition of stableequilibrium; that is, the condenser has cooled to substantially airtemperature, hence any slight increase in pressure therewithin willmerely cause some condensation of the small amount of vapor required tofill the condenser. Stated somewhat diilerently, the effect of therising column in the conduit 31 is not to increase pressure in thesystem comprising the condenser 36, conduit 35, and cooling Jacket 31but to condense a small amount of vapor. However, the increase inpressure within the cooling system caused by the application of vaporpressure to the upper part of the reservoir is applied directly andimmediately to the vapor lock by reason of the liquid contained inconduit 38 and the lower portion of conduit 40. Such an increase inpressure applied in an unbalanced manner produces a number of effectswhich will be described hereinafter.

As long as the vapor lock exists in conduits 40, 4I, and 42, a conditionof stable equilibrium .is maintained. That is, the distance between thefree surface level of liquid in conduit 40 and the free surface level ofliquid in reservoir 38 is equal to the distance between the free surfacelevels of the liquid in conduits 42 and 43. Any condition tending toupset this equilibrium will tend to eliminate the vapor lock and topermit free flow of coolant from the reservoir to the generator-absorbercooling jacket.

At switchover, when the increase in pressure in the previously activecooling system is applied through conduit 45 to the vapor space ofreservoir 38, a column of liquid is forced upwardly into the conduit 31leading to the condenser. For reasons heretofore explained, the columnof liquid rising in conduit 31 applies an excess pressure to one sideonly of the vapor lock, thus destroying the previously existingcondition of stable equilibrium. This increase in pressure has a numberof secondary effects:

(l) A mere increase in pressure will tend to cause condensation of thevapor formed in the vapor lock in the cooler portions of conduits 48,4I, and 42.

(2) The increase in pressure on the condenser side of the lock tends todisplace liquid in the conduit systems 38 to 43, inclusive, in thedirection of the cooling jacket I1.

(3) As liquid rises in conduit 40 it will reach portions of that conduitat an elevated temperature and will cool them by vaporization of a verysmall amount of liquid. This additional vapor tends further to force theliquid in the conduit systems 42 and 43 in the direction of the coolingjacket I1. This factor cools the previously highly heated portions ofthe vapor lock conduits 40, 4I, and 42 and pushes the vapor intocomparatively cold conduits which promotes con-y densation of the vaporin the lock.

(4) When the liquid columns are displaced sumciently to force vaporaround the bight portion of the U-tube 42--43, bubbles of vapor inconduit 43 lighten that column and tend to force the liquid therefrominto jacket I 1, both by direct vapor lift action and by furtherunbalancing the forces acting on opposite sides of the conduit 4I (5)Liquid owing into jacket I1 from conduit 43 is immediately vaporizedbecause that jacket is a a very elevated temperature. When a signiflcantquantity of liquid has been forced from conduit 43 into jacket I1 andvaporized, a large increase in pressure is produced in the whole lapseany vapor remaining in the conduits 40 to 42, inclusive, and thuseliminate the vapor lock.

Stated in somewhat shorter form, the effect of the increased pressure inreservoir 38 is to displace theliquid from the generator-absorber sideof the vapor lock liquid seal to allow vapor to escape directly from thelock to the condenser and to condense the vapor forming the lock bydirect application of high pressures.

The exact proportionate eifect of the abovementioned factors is notdefinitely known. It has, however, been established by actual test thatthe above-described system will eliminate the vapor lock and permit fullcirculation of the secondary cooling medium within one minute or less ofswitchover.

In Figure 2 there is shown a modified form of the invention. Since,structurally speaking, this form of the invention differs from thatdescribed in connection with Figure 1 only in certain details to behereinafter specically pointed out, the parts of the apparatus are giventhe same reference characters as those applied to identical partsdescribed hereinabove in connection with Figure 1.

Though only the lower part of the apparatus has been shown in Figure 2,it is to be understood that the portions above the break shown inconduits II, 35, 31, 31', 35', and II' of Figure 1 are in every respectidentical with` the parts above the same conduits of Figure 2 which arenot shown.

The form of the invention of Figure 2 specifically difl'ers from Figure1 only in the elimination of conduit 45 and the substitution therefor ofU-shaped conduits 50 and 50. 'The U-shaped conduit 50 opens into thereservoir 38. This conduit is arranged to have a small downward slopewith the bight of the U positioned directly over the outlet of theproducts of combustion flue I6 of the generator-absorber A. The conduit58 is arranged with the legs of the U in vertically superposed position.The lower leg of U-shaped conduit 50 opens into reservoir 38' below thenormal liquid level therein while the generator-absorber A' is operatingon a heating period. The upper end of conduit 50 opens into the upperportion of reservoir 38 above the normal liquid level maintained thereinduring the generating period of the generator-absorber A.

The conduit 50' is similarly associated with the reservoir 38. As shownin Figure 2, the conduit 50' is substantially filled with liquid, onlythe end portion of the upper leg thereof adjacent the point at which itjoins the vapor space in the reservoir 38 being free of liquid.

'I'he systemv of Figure 2 is provided with gas supply and controlmechanisms identical with those illustrated and described in connectionwith Figure 1.

As the generator-absorber A reaches the end of its heating period, thecontrol mechanism will de-energize burner I5 and energize burner I5. Theproducts of combustion then discharging through the flue I6' willimmediately vaporize a substantial amount of the liquid in the U-shapedconduit 50', which vapor will discharge through the upper leg of saidconduit into the upper vapor space in the reservoir 38. The vapor sogenerated will, by reason of the fact that conduit 31 extendsappreciably into the liquid contained in reservoir 38 and is thereforeprovided with a liquid seal with respect to the vapor space in reservoir38.

secondary system which will condense or colincrease the pressure in thevapor space in reservoir 38. Increased pressure in the vapor space inreservoir 38 will displace liquid upwardly in the conduit 31 in the samemanner as in Figure 1. Similarly, the actions which follow as aconsequence of the increased pressure applied to the vapor space ofreservoir 38 in the Figure l form of the invention follow in the samemanner in the Figure 2 form of the invention.

Shortly after the vapor lock is eliminated the liquid level in reservoir38 will drop below the lower leg of conduit 50' and no more liquid willbe supplied thereto. The liquid remaining in conduit 50 is then quicklyvaporized and the conduit is dry until the next cooling period ofgenerator-absorber A is initiated.

In the Figure 2 form of the invention, the pressure in each secondarycooling system is independent of the associated secondary cooling systemand the excess pressure applied to a localized portion of the coolingsystem at switchover is generated and retained within a localizedportion of such system.

The Figure 2 form of the invention is particularly applicable to asingle intermittent absorption refrigerating system. For example,considering only the left-hand intermittent system and its associatedcooling mechanism of Figure 2, the conduit 50', instead of being heatedby the heater for the generator-absorber A', may be heated by anauxiliary burner which the control energizes when it de-energizes burnerl5. The operation of the system under these conditions will be identicalwith that heretofore described except with respect to the manner inwhich heat is applied to the conduit 50. Under the conditions preposedimmediately above, the control 26 of the generator-absorber A would havea positive lost motion connection with the actuating element of the'switch 21 in order to provide positive control over the main burner andburner for heating conduit 50. Under these conditions the burnercorresponding to I5', for example, would merely be arranged to heat thebight portion of the U-shaped conduit 50'.

The arrangement of portions of the invention with respect to the cabinetare illustrated in Figures 3 and 4. These figures specificallyillustrate the form of the invention of Figure 1, it being understoodthat the form of the invention of Figure 2 will be arranged in asubstantially identical manner with respect to the cabinet. Only thelower rear corner of the cabinet construction is shown, as the maincondensers and evaporator and associated parts of the system will bearranged with respect to the cabinet substantially in the manner shownin United States Letters Patent 2,386,438 issued October 9, 1945, toCurtis C. Coons for Refrigeration.

The absorber-generators A and A' are located adjacent the lower rearcorners of the cabinet construction 60, substantially below theinsulated wall 6| of the refrigerating compartment 62. Thegenerator-absorbers are also in the lower portion of a rear coolingchamber 63 which extends upwardly along avvcrtical side wall of thecabinet construction. This compartment is arranged to receive air fromthe space directly beneath the refrigerating chamber 62 and also throughlouvers 64 adjacent the bottom portion thereof. 'I'he condensers 36 and36 are positioned in the chamber 63 above and between thegenerator-absorbers A and A' wherefore these elements receive coolingair unheated by a previous contact with heat rejecting elements and alsounheated by the insulated generator-absorber assembly. PrOducts ofcombustion disposal ues 66 and 66 are provided for thegenerator-absorbers A and A', respectively. The products of combustionflues convey the waste products of combustion to the upper portion ofthe chamber 63 and discharge the same through the upper end of saidchamber. The conduits 4| and 4I pass through the lower ends of the flues66 and 66 adjacent the discharge end of the generator-absorbercombustion heating ues I6 and I6'.

In Figures 3 and 4 the conduits 31 and 31 have been shown as very short.This was done to facilitate illustration. It is preferred that thevertical distance from the conduit 4l to the lower end of the condenser36 shall at least be equal to the vertical distance between the point atwhich conduit 43 connects to jacket I1 and the point at which conduit 43connects to conduit 42. This vertical head is not essential as no harmis done if liquid does back into the condenser tubes at switchover.However, by providing room for a column of liquid of the aforesaidheight which has its upper end extending upwardly into conduit 31, theapparatus is then always capable of building up a liquid head ofsuflicient height to overcome the maximum liquid back pressure headwhich can be created by the column in conduit 43 without wetting thecondenser tubes.

Theconduits connecting the cooling jackets I1 and I1' to the reservoirs38 and 38 are always exposed to the coolest available cooling air exceptfor the small portion of the vapor lock which passesvthrough theproducts of combustion flue 66. This aids in preventing too great avapor lock in the conduits 42 and 40 and also facilitates rapid collapseof the vapor 'lock upon switchover.

The foregoing invention provides a means by which avaporization-condensation type cooling system for a periodically orintermittently cooled element may be interrupted as desired by creationof a vapor lock which will be eliminated in a short period of time wheneither generator-absorber is switched over from generating to absorbingoperation without the action of moving parts within either primary orsecondary cooling systems. The sole control required is that providedfor energizing and lie-energizing the heating means for the generatorabsorbers which has no direct connection with the cooling system. Thusthe application of heat to the system simultaneously creates a iiowblocking vapor pocket in one part of the system and creates forces whichquickly eliminate another ow blocking vapor pocket.

While the invention has been illustrated and described in detail it isnot to be limited thereto but various changes may be made in theconstruction, design and arrangement of parts without departing from thespirit of the invention or the scope of the appended claims.

I claim:

1. In combination with an element subject to alternate periods ofheating and cooling; a cooling system having a heat absorbing portion inheat exchange relation with said element, a portion a ranged to form avapor lock when subjected to heat and to be heated simultaneously withthe application of heat to said element, and means for applying anexcess pressure to a portion of said vapor lock when the application ofheat to said element is discontinued. v

2. A cooling system for an element which 1s alternately heated andcooled comprising a condensing means, a reservoir, means for conductingliquid from said condensing means to said having liquid sealing trapsbetween said partand said reservoir, and a liquid vaporizing meansconnected to apply vapor pressure to said reservoir above the liquidlever therein.

3. In combination a refrigerating system iny cluding agenerator-absorber, a cooling system for said generator-absorberincluding a heat absorbing part in heat exchange relation with saidgenerator-absorber, a heat rejecting part, and a coolant reservoirconnected in circuit, said connecting means including a part arranged toconduct coolant from said reservoir to said heat absorbing part having avapor trapping part connected to said reservoir Iand said heat absorbingpart by liquid sealing traps, coolant vaporizing means connected tosupply vapor to said reservoir above the surface level of liquid thereinand in liquid sealed relationship to said heat rejecting part, and meansconstructed and arranged to heat said generator-absorber and saidcoolant vaporizing means alternately.

4. In combination a. refrigerating system including agenerator-absorber, a cooling system for said generator-absorberincluding a heat absorbing part in heat exchange relation with saidgenerator-absorber, a heat rejecting part, and means connecting saidparts in circuit including means for conducting liquid from said heatrejecting part to said heat absorbing part having a first vapor trappingpart connected to said heat rejecting part through a liquid seal, asecond vapor trapping part connected to said first vapor trapping partand said heat absorbing part through liquid seals, coolant vaporizingmeans connected to discharge vapor into said first vapor trapping part,and heating means arranged to heat said generator-absorber and saidsecond vapor trapping part simultaneously and tc heat said iirstvaporizing part alternately with respect to said generator-absorber andsaid second vapor trapping part.

5. Refrigerating apparatus comprising a pair of intermittent absorptionrefrigerating systems each including a generator-absorber, means forheating said generator-absorbers -and control means for alternatelyactivating said heating means; a cooling system for each oi' saidgenerator-absorbers each comprising a part in heat exchange with one ofsaid generator-absorbers, a heat rejecting part connected to receivevapor from said heat exchange part, a reservoir, a conduit from saidheatrej ecting part extending into the interior of said reservoir, conduitmeans extending from said reservoir to said heat exchange part includinga vapor trapping liquid flow preventing means arranged to be heatedconcurrently with said one generator-absorber, a c oolant charge in saidcooling system sufficient to seal off the end portion of said conduitextending into the reservoir when liquid accumulates in the reservoirunder the action of said iiow preventing means; and conduit meansconnecting the upper portions of said reservoirs.

6. Refrigerating apparatus comprising a pair of intermittent absorptionrefrigerating systems each including a. generator-absorber, means forheating said generator-absorbers and control means for alternatelyactivating said heating means; a cooling system for each of saidgenerator-absorbers each comprising a part in heat exchange with one oisaid generator-absorbers, a heat rejecting part connected to receivevapor from said heat exchange part, a reservoir, a conduit from saidheat rejecting part extending into the interior of said reservoir,conduit means extending from said reservoir to said heat exchange partincluding a vapor trapping liquid ow preventing means arranged to beheated concurrently with said one generator-absorber, a coolant chargein said cooling system suilicient to seal oil! the end portion ofsaidconduit extending into the reservoir when liquid accumulates in thereservoir under the action oi' said ilow preventing means, and secondconduit means associated with said reservoir arranged to receive liquidtherefrom and to be heated concurrently with the other of saidgenerator-absorbers.

7. In a refrigerating apparatus having en element subject to alternateperiods of heating and cooling, a vaporization-condensation coolingsystem having a vaporizing part in heat absorbing relationship with saidelement, a condenser connected to receive vapor from said vaporizingpart. a liquid receiver, conduit means for condcting liquid from saidcondenser to said receiver including' an end portion extending into saidreceiver to have its open end sealed when the liquid level in saidreceiver rises above a predetermined level, means for conducting liquidfrom said reservoir to said vaporizing part including a vapor entrappingliquid flow preventing part arranged to be heated concurrently with saidelement, and heat operated means arranged to be heated alternately withsaid element for applying a pressure to one portion of said owpreventing part in excess oi' the pressure on other portions of said nowpreventing part to displace vapor in said iiow preventing part in thedirection of said vaporizing part.

8. Refrlgerating apparatus comprising a pair of intermittent absorptionrefrigerating systems each including a generator-absorber, a coolingsystem for each of said generator-absorbers, each of said coolingsystems including a heat absorbing part in heat exchange relation with agenerator-absorber, a heat rejecting part arranged to receive vapor fromsaid heat absorbing part, a liquid receiving part, conduit means forconducting liquid from said heat rejecting part to said liquid receivingpart, second conduit means for conducting liquid from said liquidreceiving part to said heat absorbing part including a sectionconstructed to block ilow of liquid from said liquid receiving part whensaid section is vapor illled, means constructed and arranged to heatsaid section and the generator-absorber in heat exchange relation withsaid heat absorbing part concurrently; control means for energizing saidheating means alternately, and means constructed and arranged to `beactivated by the application of heat to each generator-absorber to applya pressure to the cooling system of the other generator-absorber todisplace liquid in the liquid receiving part of the cooling system oi'the generator-absorber which has just completed a heating cycle into theconduit leading to said heat rejecting part.

9. Refrigerating apparatus comprising a pair of intermittent absorptionrefrigerating systems each including a generator-absorber, a coolingsystem for each of said generator-absorbers, each of said coolingsystems including a heat absorbing part in heat exchange relation with ageneratorabsorber, a heat rejecting part arranged to rell ceive vaporfrom said heat absorbing part, a liquid receiving part, conduit meansfor conducting liquid from said heat rejecting part to said liquidreceiving part, second conduit means for conducting liquid from saidliquid receiving part to said heat absorbing part including a sectionconstructed to block ow of liquid from said liquid receiving part whensaid section is vapor filled, said liquid receiving means and saidconduit from said heat rejecting part being so constructed and arrangedthat the end of said conduit is submerged in liquid when said section islled with vapor, means constructed and arranged to heat said section andthe generator-absorber in heat exchange relation with said heatabsorbing part concurrently; control means for energizing said heatingmeans alternately, and means constructed and arranged to be activated bythe application of heat to each generator-absorber to apply a pressureto the liquid receiving means of the cooling system of the othergenerator-4 absorber above the liquid lvel in said receiving means todisplace liquid from said receiving means upwardly in the conduitleading to the heat rejecting part and to apply a pressure to saidsection in excess of the pressure in said heat absorbing part.

l0. Absorption refrigerating apparatus comprising a pair of intermittentrefrigerating apparatuses each having a part to be heated and cooled andmeans for heating said part, control means for energizing said heatingmeans alternately; a coolingr system including elements in heat exchangewith each of said parts, said cooling system including means to flowcoolant to said elements, said ow means having structure arranged to beheated simultaneously with the application of heat to each of saidapparatuses onerable when heated to prevent flow of coolant to said partof the apparatus being heated, and structure operable upon applicationof heat to each of said apparatuses for eliminating the ability of saidflow preventing structure to prevent the flow of coolant to the saidpart of the previously heated apparatus.

1l. In combination a heat operated intermittent absorption refrigeratingsystem including a part to be cooled when the system is producingrefrigeration, and means for intermittently heating said system; acooling system arranged to ow a coolant into heat exchange relation withsaid part to be cooled including an inverted U-shaped conduit arrangedto be heated simultaneously with the application of heat to therefrigerating system, liquid sealed traps connected to each leg of saidinverted U-shaped conduit whereby to form a sealed-oil flow preventingbody of vapor in said inverted U-shaped conduit when the same is heated,and heat operated means arranged to be heated alternately with theapplication of heat to said refrigerating system for applying a force toone side of said body of vapor to displace the same through one of saidliquid sealing traps.

12. In a refrigerating apparatus of the intermittent absorption typeembodying a part to be cooled and means for applying heat to therefrigerating apparatus; a cooling system comprising a heat absorbingpart in heat exchange relation with said part to be cooled, a heatrejecting part, means for conveying coolant from said heat rejectingpart to said heat absorbing part including a liquid sealed vapor pocketand a part arranged to be heated simultaneously with the application nfheat to said refrigerating apparatus 12 to form a trapped flowpreventing body of vapor, and means arranged to be heated alternatelywith the application of heat to said refrigerating apparatus forcreating an excess pressure in said liquid sealed vapor pocket.

13. Refrigerating apparatus comprising a pair of heat operatedintermittent absorption refrigerating systems each including a part tobe cooled and a heat absorbing element in heat exchange therewith,heating means, means for governing the operation of said heating meansto heat said systems alternately; heat rejecting means, means forconveying heated cooling medium from said heat absorbing elements tosaid heat rejecting means, separate means for conveying cooling mediumfrom said heat rejecting means to each of said heat absorbing elements,each of said conveying means including a structure operative when heatedto form a cooling medium flow blocking trapped body of cooling mediumvapor. each of said structures being arranged to be heatedsimultaneously with the refrigerating system including the heatabsorbing element to which the structure conveys cooling medium; andmeans operative when heat is applied to either of said refrigeratingsystems to introduce vapor of cooling medium into the means forconveying cooling medium in heat exchange with the other refrigeratingsystem between the heat rejecting means and the vapor trapping structurein said conveying means and in liquid sealed relation to each of them.

14. In combination with a refrigerating system having a part to becooled periodically in the operation of the system, a, cooling systemcomprising a heat rejecting part, a heat absorbing part in heat exchangewith said part to be cooled, means for conveying cooling medium fromsaid heat rejecting part to said cooling part including structurearranged to form an entrapped flow blocking body of vapor when heatedand a. liquid sealed vapor pocket, means arranged when heated to createa pressure in said vapor pocket. and means arranged to heat saidstructure and said last-mentioned means alternately.

15. In combination with a refrigerating system having a part to becooled periodically in the operation of the system, a cooling systemcomprising a heat rejecting part, a heat absorbing part in heat exchangewith said part to be cooled, means for conveying cooling medium fromsaid heat rejecting part to said cooling part including structurearranged to form an entrapped flow blocking body of vapor when heated,said conveying means being constructed and arranged to form equalpressure creating liquid column pressure heads on each side of saidentrapped body of vapor when said structure is heated, means arrangedwhen heated to create an additional pressure creating liquid column onone side of said entrapped body of vapor to destroy the previousequality of liquid column pressure heads on opposite sides thereof, andmeans larranged to heat saidstructure and said last-mentioned meansalternately.

16. In combination with a refrigerating system having a part to becooled periodically in the operation of the system, a cooling systemcomprising a heat rejecting part, a heat absorbing part in heat exchangewith said part to be cooled, means for conveying cooling medium fromsaid heat rejecting part to said cooling part including structurearranged to form an entrapped flow blocking body of vapor when heated,means arranged when heated to force liquid into heat exchange with theportion of said conveying means containing vapor when heated to promotecondensation of said entrapped vapor. and means arranged to heat saidstructure and said last-mentioned means alternately.

17. In combination with an element subject to alternate periods ofheating and cooling; a cooling system having a heat absorbing portion inheatexchange relation with said element, means for conveying coolingmedium to said heat absorbing portion including structure operative whenheated to prevent tlow of cooling medium to said heat absorbing portion,heat operated means operative when heated to cool said structure, andmeans for simultaneously applying heat to said element and saidstructure and for heating said heat operated means alternately with saidelement.

18. Refrigerating apparatus comprising a pair of intermittent absorptionrefrigerating systems each including a generator-absorber; a coolingsystem for each of said generator-absorbers, each of said coolingsystems comprising a part in heat exchange relation with a separate oneof said ing medium to said part including structure op- 141 erative whenheated to prevent now of cooling medium through said conveying means andmeans operative when heated to cool said structure; heating means. meansfor activating said heating means to heat said generator-absorbersalternately and simultaneously to heat the now preventing structure ofthe cooling system of the generator-absorber being heated and the heatoperated means oi' the other cooling system.

' CURTIS C. COONS.

REFERENCES CITED The following references are of record in the ille oithis patent:

UNITED STATES PATENTS Number Name Date 1,627,808 Schurt'z May 10, 19271,854,778 Boving Apr. 19, 1932 2,021,994 Hainsworth Nov. 26, 19352,340,886 Kleen Feb. 8, 1944 FOREIGN PATENTS Number Country Date 117.029Australia -June 10, 1943

